Vehicles such as passenger cars and trucks are equipped as standard with exterior and interior mirrors which are also known as side mirrors and rearview mirrors. The mirrors help the vehicle driver to monitor the lateral and rear surrounding area of the vehicle, for example when reversing, parking, changing lanes or turning.
It has already been recognized that the exterior and interior mirrors currently used have several disadvantages. The mirrors usually only provide the vehicle driver with a very limited viewing angle of the vehicle surroundings. So-called “blind spots” can only be compensated for by means of additional or aspherical mirrors. The known exterior and interior mirrors can only be used with difficulty or cannot be used at all in the dark. In addition, the headlights of a following vehicle, for example, can cause dazzling effects. Another disadvantage is the fact that the vehicle driver is temporarily distracted from what is happening in the traffic each time that the vehicle driver's eyes have to adapt to the modified object distances when glancing at one of the mirrors, i.e. during the so-called accommodation of the eyes. Another major disadvantage of exterior mirrors which should be indicated is their negative influence on the design and aerodynamic properties of the vehicle, in particular on the latter's flow resistance.
Due to the various disadvantages of the known exterior and interior mirrors, approaches already exist which replace the mirrors by a system which comprises one or more image capturing devices, in particular cameras, which detect the lateral and/or rear surrounding area of the vehicle, and produce image data of the corresponding area as well as one or more image reproducing devices, for example display screens, wherein the image reproducing devices are arranged in the field of vision of the vehicle driver and which continually reproduce the image data which is generated by the image capturing device. The image capturing devices are generally arranged on the left and right sides respectively in the outer area of the vehicle, for example in the area of the A-pillar with a line of vision backwards. The image reproducing devices are mostly arranged in the inside of the vehicle, also in the area of the A-pillar respectively, in the field of vision of the vehicle driver.
DE 10 2007 044 536 A1 shows such a solution, in particular for monitoring the lateral and/or rear surroundings of a vehicle, comprising recording means for capturing an image flow containing the images of at least one part of the surroundings of the vehicle, a display unit for reproducing at least one image section of the image flow in the inside of the vehicle, and means for automatically modifying the surrounding section represented by the reproduction of the image section by means of the display unit. The solution also comprises means for determining at least one earlier position of the vehicle, wherein the surrounding section can be automatically adapted in accordance with the earlier position of the vehicle.
DE 10 2007 044 536 A1 thus discloses a solution for intelligent and situation-specific adaptation of the represented section of the vehicle surroundings, which is represented by the display unit. However, the document does not disclose a satisfactory solution for vehicles with trailers and, in particular, not for commercial vehicles such as, for example, trucks.
In the case of systems which replace the left and right exterior mirrors respectively by recording means and a display unit, it can occur, for example, that, as of a certain curve radius, the trailer of the vehicle is only visible on one side in the displayed image section, i.e. the vehicle surroundings are partially or completely obscured in the image by the front side of the trailer and that, on the opposite side, an image of the vehicle surroundings is displayed, without the trailer of the vehicle being visible therein. In such a case, it is difficult for the vehicle driver to monitor the vehicle surroundings sufficiently and to correctly judge the position of the trailer in the vehicle surroundings. Carrying out particularly complex driving manoeuvers with a trailer is therefore made difficult.
In order to ensure that, in the case of vehicles with trailers, the vehicle driver can also sufficiently monitor the vicinity of the vehicle at all times with different alignments of the trailer with respect to the vehicle, i.e. at different angles of the vehicle longitudinal axis to the trailer longitudinal axis, a particular field of vision, which is also described as a “Field of vision of Class IV wide-angle mirrors”, which must likewise be visible at all times to the vehicle driver, i.e. with vehicle mirrors or with a camera-based mirror replacement system, is specified in an ISO (International Organization for Standardization) standard, in particular standard ISO 16505 in conjunction with ECE-R46 (Regulation No. 46 of the Economic Commission for Europe of the United Nations (UN/ECE)).
In the case of the known vehicle mirrors, the coverage of the prescribed “Class IV” field of vision is achieved in that the vehicle driver can freely move his head and is thus able to view the required field of vision by means of a relatively small mirror. In the case of the mirror replacement systems which are now proposed, which work with cameras and screens, it has to date only been possible to compensate for the relevant field of vision by correspondingly high resolutions and/or with large detection angles of the cameras, and by means of correspondingly large displays in the inside of the vehicle. In order for a screen which is intended to replace the right exterior mirror and which, on a vehicle in which the steering wheel is arranged on the left side of the vehicle, is to be arranged at a distance of up to 2 meters from the vehicle driver, a diameter of at least 32 inches would be required, for example, to cover the relevant field of vision. This conflicts with cost-saving and space-saving objectives and significantly influences the design of the inside of the vehicle.